During the last four decades, Iran's banking system has always been at the forefront of dealing with external impulses caused by sanctions and war. The two critical stages of "12-day war" and "40-day war" as examples of modern proxy conflicts have brought unprecedented pressure on the financial infrastructure and especially the oldest bank of the country (Sepe Bank). This research, with a comparative case study approach, seeks to identify and analyze the specific challenges of Islamic banking in Sepeh Bank in the conditions before, during and after these two wars. The research is qualitative-quantitative with a historical case study strategy. The data was collected through the analysis of bank archival documents, financial statements, confidential internal reports and in-depth interviews with 15 former senior managers of Sepeh Bank. The analysis framework is based on the adaptive model of "Financial Resilience in Crisis" (FRCM). The findings in the form of comparative tables show that in the "40-day war", the average decline in rial value of assets was 2.7 times and the withdrawal rate of deposits was 4.1 times higher than in the "12-day war". However, cybersecurity challenges are reported to be 60% more severe in the 12-day war. Also, the role of Sepeh Bank's border branches in providing liquidity to the fronts in both wars was identified as a strategic advantage and at the same time a vulnerable point. In the transition from classic war to proxy wars, Sepeh Bank has moved from logistics-field challenges to cyber-credit challenges. The main challenges in both stages have been maintaining liquidity, bypassing immediate sanctions and managing customer trust. Creating a banking cyber shield and war deposit insurance fund are suggested as policy solutions.